The present invention relates to glass balloons and to assemblies of glass balloons. A single glass balloon is valuable as an ornament and also as a device for demonstrating properties of the air. Assemblies of glass balloons may constitute a glass foam that is buoyant in air. Slabs of such air-buoyant glass foam can be used to construct artificial clouds.
The beautiful optical and mechanical properties of glass are widely admired. The delightful response of buoyant rubber balloons to the air currents in a room are also widely admired. The glass balloon combines both of these long-established attractions into a single device. Experience teaches that many persons are fascinated by the sight of a glass balloon.
The glass balloon has the further advantage of having an expected buoyant life of a hundred or a thousand times longer than the expected life of a rubber balloon of the same diameter.
Plastic or rubber balloons are widely used as indicators of outdoor air currents by professional meteorologists. Rubber and plastic balloons are not well suited, however, for studying air currents within a building. The high leakage rate of the light gas through the envelope of such a balloon destroys the ability of the balloon to maintain the equilibrium ballast condition for more than a few minutes. In contrast, the glass balloon can be easily ballasted to an equilibrium condition and will hold such ballast condition for days and so is well suited for indicating indoor air currents.
Glass foam has a wide commercial use as a foam buoyant in water, and slabs of such glass foam are used, for example, to support pipes in crossing a lake. However, no glass foam that is buoyant in air has apparently been constructed prior to this invention. By sealing the individual glass cells when most of their envelope is approximately at room temperature, this invention teaches how glass foam buoyant-in-air can be constructed. Up to the time of this invention, several experts in the construction of devices from glass have considered the construction of such buoyant-in-air glass envelopes as impractical or impossible.